KOVÁČIK Jaroslav Institute of Materials & Machine Mechanics SAS

Spoluautoři EMMER Štefan, RODRIGUEZ Jose , CA Inmaculada

The experimental samples were prepared from 37MnSi5 steel by cutting and machining. The goal of the work was to establish the maximum temperature which the steel samples can sustain during solar heating and to observe how this temperature will affect the microstructure of used steel. Then steel samples were coated by TiB2ceramic using electro spark deposition. Original and coated samples were solar heat treated using vertical solar furnace at PSA, Spain. The microstructure and micro hardness of the samples were observed before and after solar heat treatment. Due to very good thermal conductivity the TiB2 ceramic coating dissipates better the solar energy. It transfer the energy from the narrow solar focus to steel substrate in such a way that it decreases maximal temperature in steel substrate (lower maximal peak temperature, wider geometry of Gaussian thermal peak) thus preventing the steel to melt or to change the steel properties very significantly. Together with good resistance to various chemicals also at higher temperature it seems that TiB2 is promising for surface coatings of heat receivers based on steel or even nickel super alloys tubes with cooling liquid or gas inside and heated by solar radiation to temperatures up to 500 – 900°C for solar power plants. Financial support by the Access to Research Infrastructures activity in the 7th Framework Programme of the EU (SFERA Grant Agreement n. 228296) is gratefully acknowledged and also of Slovak Grant Agency (VEGA grants 2/0158/13 and 1/0189/12) and APVV VMSP II–0009–09.